The invention discloses a cleaning device for numeric-control machining centers. The cleaning device comprises a first mounting rod, a rotation plate and a second mounting rod; a connection rod is movably inserted into the inner wall of the first mounting rod; the other end of the connection rod is movably inserted into the second mounting rod; a mounting block is welded at the end, far away fromthe connection rod, of the first mounting rod; the rotation plate is rotatably mounted on the mounting block through a pin shaft; and electromagnet is embedded at a middle position on the front surface of the rotation plate; lining plates are symmetrically welded at two sides of the front surface of the rotation plate; rotation shafts are rotatably mounted on the front surfaces of the lining plates; a mounting plate is welded at one end, far away from the connection rod, of the second mounting rod; and a brush is movably inserted into a middle position on the lower surface of the mounting plate. The cleaning device is simple in principle, relatively comprehensive in function and convenient to use and is capable of effectively cleaning chips in the machining centers.